Biodiversity & Conservation

Native oyster - Ostrea edulis

Ostrea edulis

Image Keith Hiscock - A view of the upper (right) side of a native oyster attached to pebbles. Image width ca 5 cm.
Image copyright information

  • #
  • #
Distribution map

Ostrea edulis recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

Sightings Have you seen Ostrea edulis?
If so please submit your record.

  • UK_BAP
  • OSPAR
Taxonomy icon Taxonomy Taxon English term
Phylum Mollusca Snails, slugs, mussels, cockles, clams & squid
Class Bivalvia Clams, cockles, mussels, oysters, and scallops
Authority Linnaeus, 1758
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Widely distributed around the British Isles but less so on the east and north-east coasts of Britain and Ireland. The main stocks are now in the west coast of Scotland, the south-east and Thames estuary, the Solent, the River Fal, and Lough Foyle.
Habitat information icon Habitat information Ostrea edulis is associated with highly productive estuarine and shallow coastal water habitats on firm bottoms of mud, rocks, muddy sand, muddy gravel with shells and hard silt. In exploited areas, suitable habitat is/has been created in the form of 'cultch' - broken shells and other hard substrata.
Text page icon Description Ostrea edulis is a bivalve mollusc that has an oval or pear-shaped shell with a rough, scaly surface. The two halves (valves) of the shell are different shapes. The left valve is concave and fixed to the substratum, the right being flat and sitting inside the left. The shell is off-white, yellowish or cream in colour with light brown or bluish concentric bands on the right valve. Ostrea edulis grows up to 110 mm long, rarely larger. The inner surfaces are pearly, white or bluish-grey, often with darker blue areas.
Identifying features
  • Shell inequivalve, lower (left) valve convex and upper valve flat sitting within the lower.
  • Periostracum thin, dark brown.
  • Outer surface rough and scaly with concentric sculpture and fine radiating ridges.
  • Yellowish or cream in colour with light brown or bluish concentric bands on the right valve.
  • Hinge line without teeth in the adult.
  • Adductor muscle scar white, or slightly discoloured.
Additional information icon Additional information Also commonly known as the flat oyster and European oyster.

Want to know more? more

This review can be cited as follows:

Angus Jackson & Catherine Wilding 2009. Ostrea edulis. Native oyster. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 09/09/2010]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3997>